Increasing the demand for the surface quality of optics, such as high-power laser, space optics, and aerospace, the development of optical polishing and fabrication techniques have been investigated. Especially, high quality and ultra-precision optical surface are significantly required for shorter wavelength due to diffraction limit. Ion beam figuring (IBF) have been used a high-end method of correcting errors on an optical surface at atomic level by sputtering, which is suitable for last processing steps. Lately, we have successfully developed a gas cluster ion beam (GCIB) that is used as a sputtering or primary ion beam for time-of-flight secondary ion mass spectrometry (ToF-SIMS). Here, we applied GCIB to polish and fabricate for several optical substrates including UV and VUV mirrors. To demonstrate this technique, we considered the GCIB parameters such as beam diameter, irradiation time, incidence angle of GCIB, and gases driving the cluster ion source. During the experiments, we used an electron flood gun to compensate surface charging on the optics. We also measured roughness profiles and surface textures in terms of before and after polishing using coherence correlation interferometry (CCI). We will discuss development possibility of GCIB as a new technique of polishing and fabrication for optical substrates.
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